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The State of Statoliths

Squids make statoliths, an important part of their balance organ, from calcium carbonate. But increasing atmospheric carbon dioxide levels is causing ocean acidification, which reduces carbonate in the oceans and may make it difficult for animals to make and maintain such structures in the future. MIT-WHOI Joint Program student Max Kaplan and biologist Aran Mooney raised squids in seawater with normal and high levels of carbon dioxide showed that squid from high-carbon-dioxide water (left) produced smaller, more misshapen statoliths than squids from normal seawater (right). (Image courtesy of T. Aran Mooney, Woods Hole Oceanographic Institution)